Tejas Mk.2: News & Discussions - 25 February 2018

ramana · Post by **ramana** » 30 Mar 2018 21:13

And even if the give a name, till you see the results. Reason is the name moves on.

ragupta · Post by **ragupta** » 01 Apr 2018 21:00

Waiting for anyone to hold development of Tejas Mk2 would be criminal conspiracy against the country and development of MIC.
For the requirement - ADA/HAL should move with the existing known requirement with Mirage 2000 Baseline, that IAF wanted as their MCA not long time ago, along with what they had desired in Tejas Mk1/A leaving out the unobtanium items for now. Incorporating features that Navy desired in Naval LCA.

The design should be optimized around a GE-F414 powerplant (replaceable for similar size powerplant ) category for
- range and efficient size (Gripen and F-16, M2k should be guideline)
- AESA radar
- BVR missiles
- refueling probe
- most advanced avionic locally available.
- bomb and missile delivery that are locally developed.

What else can one desire more from a fighter?

ramana · Post by **ramana** » 01 Apr 2018 21:52

I think we can soon rename Tejas Mk2 as MCA.

As the quantity will be 201 and could be higher eventually, should get the name changed.

fanne · Post by **fanne** » 02 Apr 2018 01:19

will the wings of LCA mk 2 will be same in size and shape as MK1 or will it be proportionally enlarged?

Haridas · Post by **Haridas** » 02 Apr 2018 03:33

ragupta wrote:What else can one desire more from a fighter?

Many more things of course:
1. western sensors and multi-sensor fusion software
2. able to land on basketball field,
3. western missiles and PGM
4. 4000km range with 8 tonne payload
5. Invisible on RF, IR, Visual band
6. must cost at least $0.15 Billion/unit
7. laser gun

Please don't ask for dangerous wish list of yank inspired fighter jockeys. Pardon my rhetorics.

Added later: Must not use the heavy composites but instead use strong but light aerogel https://en.wikipedia.org/wiki/Aerogel

Haridas · Post by **Haridas** » 02 Apr 2018 03:44

fanne wrote:will the wings of LCA mk 2 will be same in size and shape as MK1 or will it be proportionally enlarged?

If I were IAF and ADA, I would want to see MahaTejas capability envelop expanded to be more capable on BVR combat & increased range, albiet without increasing G load rating from current 8G.

IOW keep current wing, house bigger radar thus increase nose cone diameter (and length to keep same wave-drag load), fatter and longer fuselage.

Neshant · Post by **Neshant** » 02 Apr 2018 03:50

*poof*

ragupta · Post by **ragupta** » 02 Apr 2018 03:51

Haridas wrote:
ragupta wrote:What else can one desire more from a fighter?
Many more things of course:
1. western sensors and multi-sensor fusion software
2. able to land on basketball field,
3. western missiles and PGM
4. 4000km range with 8 tonne payload
5. Invisible on RF, IR, Visual band
6. must cost at least $0.15 Billion/unit
7. laser gun

Please don't ask for dangerous wish list of yank inspired fighter jockeys. Pardon my rhetorics.

===

Hope IAF get realistic and help built local MIC, with the same zeal that they desire the imports.

srai · Post by **srai** » 02 Apr 2018 06:56

fanne wrote:will the wings of LCA mk 2 will be same in size and shape as MK1 or will it be proportionally enlarged?

Original plan was to be as minimal change as possible. The main changes planned were the addition of a 0.5m or 1m plug and other minor airframe refinements. Lately, there has been talk of an addition of canards.

Internal rearrangement, external jammer and AESA are being done as part of Mk.1A. That will port over. There are other refinements to the plugin interfaces and an internal UEWS.

srin · Post by **srin** » 02 Apr 2018 07:12

I'd half-joking when I asked the questions two weeks ago ...

- Tejas Mk1 is lighter than Gripen C/D and has more powerful engines. Yet, Tejas is underpowered / 3-legged cheetah.
- If Gripen E actually first flew in 2016, what did we test for MMRCA trials ?
- If Gripen E was evaluated for MMRCA, does that mean Tejas Mk2 is now MMRCA contender ?

And now we see Mk2 will now be MCA. I sincerely hope that it is only a label change, and not a goalpost change.

Here's my concern: the MK2 was required because Tejas was overweight and F404 engine's thrust wasn't enough. So we needed to add a more powerful engine. So we had competition between F414 and EJ200 and F414 won. Everyone knows this.

But if we are going to have higher empty weight and MTOW of Tejas Mk2, and want it to be like a Mirage-2000 (which is powered by a much higher thrust and heavier M-53 engine), aren't going to have the same issue ? Isn't the Tejas Mk2 going to be overweight even when powered by F414 ?

To me this looks like classic case of scope creep.

Dileep · Post by **Dileep** » 02 Apr 2018 08:11

'Goalpost move' is dudespeak for 'scope creep' in mbagiri.

It goes like this:

Tejas is overweight. Can't take it.
Look, we got bigger injin saar. Can you take it now?
You got a bigger injin, so, can't you get this, that and the other, and name it MahaTejas.
Got this, that and other and named it MahaTejas. Can you take it now?
MahaTejas is overweight. Can't take it.
...........

srin · Post by **srin** » 02 Apr 2018 08:41

I'm trying to compute and compare the TWR of Mk1 and Mk2. I got the Mk1 specs from wiki: https://en.wikipedia.org/wiki/Thrust-to ... r_aircraft

Is TWR normally computed on the empty weight or the MTOW and is the thrust the dry thrust or wet thrust ?

SaiK · Post by **SaiK** » 02 Apr 2018 10:24

span is + 0.7m more for Mk2. if those two refuellers can be tucked in (spaced/conformal or under blended wings), we can easily see couple of light-weight brahmos++ version in place of those drops.

Haridas · Post by **Haridas** » 02 Apr 2018 10:29

srin wrote:I'm trying to compute and compare the TWR of Mk1 and Mk2. I got the Mk1 specs from wiki: https://en.wikipedia.org/wiki/Thrust-to ... r_aircraft

Is TWR normally computed on the empty weight or the MTOW and is the thrust the dry thrust or wet thrust ?

max thrust, thus wet thrust.

Haridas · Post by **Haridas** » 02 Apr 2018 10:33

Dileep wrote:'Goalpost move' is dudespeak for 'scope creep' in mbagiri.

It goes like this:

Tejas is overweight. Can't take it.
Look, we got bigger injin saar. Can you take it now?
You got a bigger injin, so, can't you get this, that and the other, and name it MahaTejas.
Got this, that and other and named it MahaTejas. Can you take it now?
MahaTejas is overweight. Can't take it.
...........

What's the problem? Make it twin engine then.

Haridas · Post by **Haridas** » 02 Apr 2018 10:38

SaiK wrote:span is + 0.7m more for Mk2. if those two refuellers can be tucked in (spaced/conformal or under blended wings), we can easily see couple of light-weight brahmos++ version in place of those drops.

Rambha will become jobless then. Let the fist comprise differently abled fingers, each with appropriatly differentiated function.

Austin · Post by **Austin** » 02 Apr 2018 10:42

Looking at Tejas Mk1 fly at AI , it flies as well as Gripen-NG or F-16 latest block does , So thrust is as good as any thing flying out there of its class.

Mk2 wont be medium fighter but a Mark-2 model of Mk1 , much like Gripen-NG wont be a medium fighter either , In most practical situations you rarely fly with full weapon full fuel , thats a rare thing if that even happens in any sortie for any fighter.

As thumb rule its always half the payload and fuel if you have a longer run way you can take full fuel with drop tanks or just top it up but payload would remain to 40-50 % of the advertised payload so prevent stress on airframe

fanne · Post by **fanne** » 02 Apr 2018 16:50

srai wrote:
fanne wrote:will the wings of LCA mk 2 will be same in size and shape as MK1 or will it be proportionally enlarged?
Original plan was to be as minimal change as possible. The main changes planned were the addition of a 0.5m or 1m plug and other minor airframe refinements. Lately, there has been talk of an addition of canards.

Internal rearrangement, external jammer and AESA are being done as part of Mk.1A. That will port over. There are other refinements to the plugin interfaces and an internal UEWS.

My question is different- Most of the testing in an airplane is around the wing. Then one can always fatten the spine or have conformal tanks etc etc with the same wing. Little testing required, faster service.
Now we know, in LCA mk 2 we will have a plug (.5m), we may have canards (that would mean heavy testing of the FCS), hopefully no redesign of air intakes (or could be to overcome known issue - some testing) - In this case will the wing area still remain the same, i.e. wing size is same? Or the wing will also expand proportionally (while shape may remain same)? I was more thinking, how easy is to have a identical shape wing, but bigger in size (afterall wind tunnel model and real planes have similar shape, but size is significantally different). In worst case, if we are denied f414 engines and what not (may not happen euesaa wants us to be counterweight to chin), can we then have a LCA sorry single engine MCA with MKI engines.

srai · Post by **srai** » 02 Apr 2018 20:02

^^^
Things can't be scaled up as easily as one might think. Optimal design (150% breaking point for wings) takes time to arrive at. So do qualifications. One example I read about long ago was F-18 A/B/C/D to E/F scaling up had wing-drop problem that was discovered quite late in the flight testing phase.

fanne · Post by **fanne** » 02 Apr 2018 20:38

So then, the body may get elongated, but the wing will remain the same, effectively keeping lift same, but increasing weight, impacting acceleration, turn ratio etc etc. Not a bad bargain, if that increases range, volume (say for internal jammer), weapon load etc.

ArjunPandit · Post by **ArjunPandit** » 02 Apr 2018 21:21

One area that we can't afford to miss is N-LCA. While the IAF order hogs the light, in future for active deployments NLCA would play significant role. We must focus on our efforts to finish the NLCA on back of IAF support. It will be essential to us for any form of future carrier jet aviation.

fanne · Post by **fanne** » 02 Apr 2018 22:12

Is there a true role for NLCA. Few things that naval planes require (more than AF version) - 1)Longer range - It has to protect it's ship at a longer distance, be on patrol fro a longer time (flying and landing at deck is tough and the best Navy can only do so many sorties from a deck). You need not so light plane that carries excessive fuel to do that. 2) More safety, two engines better than one, ditching in sea is no fun, hard to find etc etc. (or else a very very reliable engine/plane). 3) At least 1 hard point and enough ground clearance to carry a heavy ASh missile (Brahmos).
NLCA overall maybe a good tech learning to eventual 2 engine M(L)CA- Maybe some smaller number NLCA fielded to overcome non availability of planes like current day (issues with Mig 29)

Indranil · Post by **Indranil** » 02 Apr 2018 22:14

There is no chance of a AL-31 powered Tejas. If F414 falls through (very unlikely), it will be EJ200 based. Frankly, I don't understand the need to conflate the requirement. LCA is a technologically advanced light aircraft. AMCA will be the medium, and FGFA may be the heavy platform. As Abhibushan sir said, there may actually be space below the LCA to lower the cost of every day mug moving. And advanced Hawk is not it.

The wing will not be redesigned on LCA-Mk2. It will be pushed outboard on the NLCA-Mk2. On the LCA-Mk2, there will be no change. The canard is not going to be a control canard. So testing it is similar to testing the LEVcon. Of course, NLCA Mk1 testing did not proceed to the stage where the LEVcons were made active (driven by FCS). None the less the FCS team have experience with the slats and flaperons. The FCS is the true jewel of the LCA program. That team is super sure of the canard.

Kartik · Post by **Kartik** » 02 Apr 2018 22:36

Indranil wrote:There is no chance of a AL-31 powered Tejas. If F414 falls through (very unlikely), it will be EJ200 based. Frankly, I don't understand the need to conflate the requirement. LCA is a technologically advanced light aircraft. AMCA will be the medium, and FGFA may be the heavy platform. As Abhibushan sir said, there may actually be space below the LCA to lower the cost of every day mug moving. And advanced Hawk is not it.

Who was seriously suggesting Al-31 for the Tejas? That would push the Tejas into the J-10 category, and the J-10 empty weight is speculated to be ~ 8850 kg, i.e. greater than that of a Mirage-2000. It will be the F-414, any other engine and we will not see the Mk2 appearing anytime before mid-2020s.

The wing will not be redesigned on LCA-Mk2. It will be pushed outboard on the NLCA-Mk2. On the LCA-Mk2, there will be no change.

Correct. There was no plan for that anytime. It is already a very large area wing, with low span. Increasing the aspect ratio of the wings by pushing the wings out will help.

The canard is not going to be a control canard. So testing it is similar to testing the LEVcon. Of course, NLCA Mk1 testing did not proceed to the stage where the LEVcons were made active (driven by FCS). None the less the FCS team have experience with the slats and flaperons. The FCS is the true jewel of the LCA program. That team is super sure of the canard.

What? not a control canard, meaning it will be fixed? Earlier you'd indicated that they will be fully moving canards, so when did this change?

brar_w · Post by **brar_w** » 02 Apr 2018 22:42

The idea of putting an AL-31 pops up every now and then. As Indranil, I and others have pointed out time and time again, this will result in an overall growth in size to compensate for the larger engine. If there is any issue with weight, best to invest in a higher power variant of the F-414 or EJ200 to compensate rather than adding AL-31 or F100 based solution which will require quite a dramatic re-design.

ramana · Post by **ramana** » 02 Apr 2018 22:58

Brar_w, There was an Av Week article in mid 90s on the weight partial for Tejas for every 1 kg weight of the engine. Some thing of the order of 2-3 kg. Structure, fuel tank, fuel etc.

SaiK · Post by **SaiK** » 03 Apr 2018 05:50

Changing course from Brahmos to Astra BVR, which platform is more suitable to cue in an net-centric buddy mode ops?

Tejas or Rambha? Can Rambha liverage full capability of Astra specifically buddy-mode lock on targets?

fanne · Post by **fanne** » 03 Apr 2018 07:50

Sorry that I keep on bringing the AL31 for LCA. It is to only cover if F414 is denied (and not to cover any shortfall). I don't think that is going to happen, as US wants us as a counterweight to chin and they will be happy to give us our Tejas (I think they have abandoned their najayaj aulaad to our west). But if they deny us for whatever reason, west may follow suite, and we will have only AL-31F as an option. Not a bad option either. Letting it be known, only will dissuade anyone denying us the F414.

Indranil · Post by **Indranil** » 03 Apr 2018 09:13

Kartik wrote:
The canard is not going to be a control canard. So testing it is similar to testing the LEVcon. Of course, NLCA Mk1 testing did not proceed to the stage where the LEVcons were made active (driven by FCS). None the less the FCS team have experience with the slats and flaperons. The FCS is the true jewel of the LCA program. That team is super sure of the canard.
What? not a control canard, meaning it will be fixed? Earlier you'd indicated that they will be fully moving canards, so when did this change?

It will be an all moving canard but not a control canard. Same as Rafale and GRipen and different from EF.

JayS · Post by **JayS** » 03 Apr 2018 09:20

Indranil wrote:
Kartik wrote:

What? not a control canard, meaning it will be fixed? Earlier you'd indicated that they will be fully moving canards, so when did this change?
It will be an all moving canard but not a control canard. Same as Rafale and GRipen and different from EF.

If its not a free floating canard how its different..?

SKrishna · Post by **SKrishna** » 03 Apr 2018 11:13

So if the canard is all moving but not a control canard and the FCS doesn’t control it then is it manually operated at fixed deflection angles like the LEVCONS on the NLCA?

brar_w · Post by **brar_w** » 03 Apr 2018 15:07

It is to only cover if F414 is denied (and not to cover any shortfall).

As many have said earlier, that makes no sense. If one were to go down the road of hypotheticals, then one would have to assume that an alternative to the F-414 would be the EJ200, M-88 family or an RD-33 derivative. The AL-31 is much larger, heavier, powerful and not in the same class. That said, GE is a reliable supplier to the Gripen and other international programs and no such "denials" will happen on the Tejas provided the F-414 is ordered in the first place (the announcement happened years ago but no solid order has yet been definitized).

JayS · Post by **JayS** » 03 Apr 2018 15:45

folks, enough of Al31FP in Tejas MK2 thread. If you want, go to "Build your own Aircraft" and pour your heart out there. Any more post with Al31 in it will be "poof"ed.

Viv S · Post by **Viv S** » 03 Apr 2018 16:42

JayS wrote:If its not a free floating canard how its different..?

I believe he means it'll be a close coupled canard rather than an uncoupled one such as on the EF or MKI. I think they're both technically free floating though.

Trikaal · Post by **Trikaal** » 03 Apr 2018 19:11

Rafale has close coupled canards. Recently, there was an article about Rafale canards bearing too much stress which could cause cost escalation due to frequent breakdown.
https://bharatkarnad.com/2017/12/10/raf ... -problems/
Is this correct? And would Tejas Mk2 face similar problems since it also has the close coupled canards and delta wing configuration?

P.S.- I know Bharat Karnad is heavily biased against anything non-russian but he does present some logical arguments in this article.

Viv S · Post by **Viv S** » 03 Apr 2018 20:49

Trikaal wrote:Rafale has close coupled canards. Recently, there was an article about Rafale canards bearing too much stress which could cause cost escalation due to frequent breakdown.
https://bharatkarnad.com/2017/12/10/raf ... -problems/
Is this correct? And would Tejas Mk2 face similar problems since it also has the close coupled canards and delta wing configuration?

P.S.- I know Bharat Karnad is heavily biased against anything non-russian but he does present some logical arguments in this article.

Seeing that its Bharat Karnad, you can be quite safe in assuming that he doesn’t know what he’s talking about on any matter that is even remotely technical. His pieces on geopolitics and strategic issues are fairly kooky as well although that can be justified as ‘opinion’ (as opposed to military matters where he’s just flat out ignorant).

The Rafale has clocked over 200,000 flight hours in 17 years. It has its drawbacks but the choice of canards has never been one of them.

Indranil · Post by **Indranil** » 04 Apr 2018 00:23

Yes, it will be close coupled. It won't be used for pitch control (at least not primarily).

JayS · Post by **JayS** » 04 Apr 2018 09:40

Viv S wrote:
JayS wrote:If its not a free floating canard how its different..?
I believe he means it'll be a close coupled canard rather than an uncoupled one such as on the EF or MKI. I think they're both technically free floating though.

I have no confusion regarding whether its closed coupled or long coupled (or uncoupled, whichever way you like to call it). I know what exactly they are planning in that regards.

A free floating canard would have no actuator for it. It would be spring loaded (or some other type of dampener) and would be free to rotate whichever way wind forces it into. (LE Slats are often free floating for example).

If it has actuator it is controlled canard. Yes, desgree of control can vary.

I do not know of any aircraft with free floating canard. Gripen FCS lets the canard freely float only during recovery from extreme envelop points or something like that.

Raman · Post by **Raman** » 04 Apr 2018 14:01

If I understand what indranil is saying, the canards will be driven by actuators but used only to manage the vortices over the wing rather than for pitch control. I would expect the latter to require radical changes to the flight control software.

Indranil · Post by **Indranil** » 04 Apr 2018 20:09

You are right sir. Frankly, I am a bit perplexed by Jay's confusion. He knows exactly how it will look like.